F, Cl and Br are elements each having seven valence electrons. Which of these:i. has the largest atomic radiusii. is most reactive?Justify your answer stating reason for each.

i. F, Cl, and Br all are in the same group and thus have the same effective nuclear charge. Br has the largest atomic radius among all because it uses the largest number of electron energy levels since the valence electrons are placed in larger orbitals i.e. the principal quantum number increases on going down the group.

ii. Fluorine is the most reactive as it has the greatest tendency to gain electrons because it has a higher effective nuclear charge and uses fewer energy levels than Br and Cl.